1. Field of the Invention
This invention relates to mechanical seals for sealing between relatively rotating elements and more particularly to split mechanical face seals.
2. Background Art
Mechanical face seals are used with a wide range of equipment, for example, turbines or pumps, that have a housing and a shaft which rotates relative to the housing. Similarly, a large number of pumps, compressors, mixers and agitators in chemical process industries, refineries and petrochemical industries, as well as a number of other industries, utilize packed stuffing boxes around their rotating shafts. It has been found generally desirable to replace the packing in stuffing boxes with mechanical face seals for reducing high maintenance costs, preventing environmental contamination, reducing product loss and for other reasons.
Failure or operational deterioration of mechanical seals also is a problem. Repair or replacement of parts of such seals may be difficult due to the inaccessible location in the equipment of the component parts. Often, because of the design of the equipment, it is difficult or impossible to remove a damaged seal component beyond the shaft end or to install a replacement component. Repair of the equipment in those cases requires entire disassembly, replacement and reassembly of the housing and component parts of the seal and the equipment.
Replacement of packing or repair of damaged seals has been facilitated by seal designs where a portion or all of the component parts of the mechanical seals are segmented or split. Installation of split or partially split seal components can be performed without necessitating the complete breakdown of the equipment and without having to pass the annular seal over an end of the shaft. Examples of split or partially split seals can be found in U.S. Pat. Nos. 3,025,070, 3,184,244, 4,423,878, 4,575,098, 4,576,383 and 4,576,384. Although the devices taught by these patents may have been appropriate for the purposes for which they were intended, each of the designs disclosed therein is either overly complicated by an overabundance of component parts or disposed toward designs which have short periods between seal failures.